On our afternoon live show The Final Round, we asked Lewis what part of the market might become the next “big short.” He was hesitant to answer, saying, “You’re asking the wrong person. Everybody will be a little stupider, if I answer that question. Can I answer this way: When people roll in with some big prediction, and they actually seem really certain about it, be very suspicious of them… When people come at you and say, ‘Oh, this is the short,’ it’s an interesting exercise, but the more serious they are about their prediction, the less seriously you should take them.”

But after the live show, Lewis thought of the NFL: “The NFL has real business problems. The CTE issues… I’ll give you the next short: the NFL.”

It’s an interesting thought: after the league has weathered so many scandals and PR issues over the last few years, from head injuries to domestic violence cases to political protests, might this season truly be the beginning of a decline for football? To put it in Wall Street terms: the NFL has enjoyed a long bull market, and bull markets eventually come to an end.

Lewis, an influential thinker on sports leagues and their finances, may be on to something. On the other hand, he added that practically speaking, he’s not sure how a person would go about shorting the NFL just yet.